Boosted by a recent victory in Colorado, an environmental group is expanding its legal campaign to try stop coal mining over climate change by challenging permits for some of the largest mines in the West.

This time, New Mexico-based WildEarth Guardians is asking a federal judge to block mining at the Antelope and Black Thunder mines in Wyoming's Powder River Basin, the El Segundo mine in New Mexico and the Bowie No. 2 mine in Colorado but it's taking the argument further.

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Rather than just saying that federal regulators should take the climate change impacts of individual mines into account before approving permits, the group claims that they should be looking at the cumulative effect of mining as a whole and whether the nation should allow any more.